@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+JP:wght@400;500;700&display=swap');

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  background-color: #1a1a2e;
  color: #ffffff;
  font-family: 'Noto Sans JP', sans-serif;
  font-size: 15px;
  font-weight: 400;
  line-height: 1.9;
}

a {
  color: inherit;
  text-decoration: none;
}

/* ナビゲーション */
.nav-logo {
  display: block;
  padding: 28px 0 12px;
  font-size: 20px;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: #fff;
  width: 640px;
  margin: 0 auto;
}

.nav-links {
  display: flex;
  align-items: stretch;
  padding: 0;
  border-bottom: 0.5px solid rgba(255, 255, 255, 0.1);
  width: 640px;
  margin: 0 auto;
}

.nav-links a {
  font-size: 15px;
  color: rgba(255, 255, 255, 0.5);
  letter-spacing: 0.06em;
  padding: 10px 16px 14px;
  display: block;
}

.nav-links a:first-child {
  padding-left: 0;
}

.nav-links a:hover {
  color: #fff;
}

.nav-links a.active {
  color: rgba(255, 255, 255, 0.9);
}

.nav-sep {
  color: rgba(255, 255, 255, 0.2);
  font-size: 11px;
  user-select: none;
  display: flex;
  align-items: center;
}

/* ブレッドクラム */
.breadcrumb {
  padding: 10px 0 12px;
  font-size: 11px;
  color: rgba(255, 255, 255, 0.3);
  letter-spacing: 0.04em;
  border-bottom: 0.5px solid rgba(255, 255, 255, 0.1);
  width: 640px;
  margin: 0 auto;
}

.breadcrumb a {
  color: rgba(255, 255, 255, 0.3);
}

.breadcrumb a:hover {
  color: rgba(255, 255, 255, 0.7);
}

.breadcrumb span {
  color: rgba(255, 255, 255, 0.15);
  margin: 0 6px;
}

/* メインコンテンツ */
.content {
  width: 640px;
  margin: 0 auto;
  padding: 32px 0 64px;
}

/* FAB（↑ボタン） */
.fab {
  position: fixed;
  bottom: 20px;
  right: 20px;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  border: 0.5px solid rgba(255, 255, 255, 0.15);
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(255, 255, 255, 0.04);
  cursor: pointer;
  z-index: 100;
}

.fab:hover {
  background: rgba(255, 255, 255, 0.08);
}

/* フッター */
footer {
  padding: 24px 0;
  border-top: 0.5px solid rgba(255, 255, 255, 0.1);
  text-align: center;
  font-size: 11px;
  color: rgba(255, 255, 255, 0.25);
  letter-spacing: 0.04em;
  width: 640px;
  margin: 0 auto;
}

/* レスポンシブ */
@media (max-width: 680px) {
  .nav-logo {
    width: 100%;
    padding: 18px 20px 10px;
    font-size: 18px;
  }
  .nav-links {
    width: 100%;
    padding: 0 20px 12px;
    flex-wrap: wrap;
  }
  .nav-links a {
    font-size: 14px;
    padding: 4px 10px 4px 0;
  }
  .breadcrumb {
    width: 100%;
    padding: 10px 20px 12px;
  }
  .content {
    width: 100%;
    padding: 24px 20px 56px;
  }
  footer {
    width: 100%;
    padding: 20px;
  }
}